Evidence for Simultaneous Dearomatization of Two Aromatic Rings under Mild Conditions in Cu(I)-Catalyzed Direct Asymmetric Dearomatization of Pyridine
作者:Michael W. Gribble、Richard Y. Liu、Stephen L. Buchwald
DOI:10.1021/jacs.0c04486
日期:2020.6.24
5-Cu-migration beginning with a doubly dearomative imidoyl-Cu-ene reaction. Kinetics, substituenteffects, computational modeling, and spectroscopic studies support the involvement of this unusual process. In this pathway, the CuL2 fragment subsequently mediates a stepwise Cope rearrangement of the doubly dearomatized intermediate to the give the C4-functionalized 1,4-dihydropyridine, lowering a second barrier
Isotopic probes for ruthenium-catalyzed olefin metathesis
作者:Justin A. M. Lummiss、Adrian G. G. Botti、Deryn E. Fogg
DOI:10.1039/c4cy01118j
日期:——
13C-labelled Grubbs catalysts, RuCl2(L)(PCy3)(13CHR) (R = H, Ph), pinpoint the fate of the methylidene (benzylidene) moiety during metathesis and deactivation.
Conversion of nitrosobenzenes to isoxazolidines: an efficient cascade process utilizing reactive nitrone intermediates
作者:Jun Yong Kang、Alejandro Bugarin、Brian T. Connell
DOI:10.1039/b806374e
日期:——
Reactive nitrones can be generated directly in situ by an unusual reaction of nitrosobenzene with styrene.
反应性氮烯可以通过亚硝基苯与苯乙烯的不寻常反应在原位直接生成。
Asymmetric Synthesis and Stereochemical Assignment of <sup>12</sup>C/<sup>13</sup>C Isotopomers
作者:Tomoya Miura、Takayuki Nakamuro、Yuuya Nagata、Daisuke Moriyama、Scott G. Stewart、Masahiro Murakami
DOI:10.1021/jacs.9b07181
日期:2019.8.28
A synthesis of chiral hydrocarbons having C1 axis and C3 symmetry, which owe their chirality due to asymmetrical distribution of 12C/13C isotopes, is reported. Their absolute configurations assigned using the vibrational circular dichroism (VCD) technique conform with those deduced from the absolute configurations of the parent α-formyl cyclopropanes.
NMR Observation of Indanyl Carbenium Ion Intermediates in the Reactions of Hydrocarbons on Acidic Zeolites
作者:Teng Xu、James F. Haw
DOI:10.1021/ja00101a044
日期:1994.11
reactions of styrene and methylstyrene on the acidic zeolites HZSM-5, HY, and H-mordenite. The results are introduced and discussed in the context of our recently proposed reclassification of typical zeolites as strong acids rather than superacids. We also show that the observation of indanyl cations but not simply phenylcarbenium ions as persistent species in high concentration is an expected consequence